In the first episode of Doctor Stranger, a gifted South Korean doctor, Park Chul(played by Kim Sang Joong), went over to North Korea to operate on Kim Il Sung.
Jang Suk Joo(played by Cheon Ho Jin) came to Chul and suggested him to cross the border to North Korea to give Kim Il Sung a heart surgery. He said this was the only way to stop the war.
Chul decided to go the North Korea, so he called his son’s mother who lived in America. He asked her to take care of their son, Park Hoon(played by Lee Jong Suk), but she got mad at him and refused to. Chul had no choice but to take Hoon to North Korea with him.
In North Korea, Chul successfully performed the surgery, and Kim Il Sung kept his promise from starting the war. Hoon, who watched everything, started to dream of becoming a great doctor like his father.